When the Riverhead Sewer District finishes its plant upgrade its facility off Riverside Drive, the water being currently treated at the plant would then be pumped through a new, high-tech filtration system before reaching Peconic Bay. (Credit: Paul Squire, file)

Mechanical failure led to Riverhead Town’s sewage treatment plant dumping improperly treated sewage into the Peconic River on three different occasions last month, according to the Suffolk County health department.

Michael Reichel, the town’s sewer plant superintendent, confirmed Friday the plant exceeded the amount of fecal coliform bacteria it is permitted to discharge into the Peconic on Nov. 26, as well as two other days in November, Nov. 5 and Nov. 19.

The town has not been issued a violation “yet”, Mr. Reichel said.

Another incident occurred in August.

The state Department of Environmental Conservation issued a Notice of Violation to the town Thursday, saying the town had until Jan. 5 to respond with a corrective action plan, said Aphrodite Montalvo, a DEC spokeswoman.

The town could be fined up to $37,500 for each incident, Mr. Reichel said.